Food Lipids: Chemistry, Nutrition, and Biotechnology

of energy: a given amount of fat contains more than twice the calories (9 kcal/g) of
other macronutrients such as proteins and carbohydrates (4 kcal/g). An ‘‘ideal’’ fat
substitute must look and function like fat and be able to substantially reduce caloric
contributions to food. In recent years, health-conscious consumers have shown interest
in reducing calories from fat by modifying their diets, exercising, and eating
healthier foods. Recent survey results show that consumers are ready for fat substitutes
and replacers in their foods (6).
II. CLASSIFICATION OF FAT REPLACERS
Fat replacers are divided into two main groups: fat mimetics and fat substitutes. They
are classified as carbohydrate-based, protein-based, and lipid-based fat replacers (Table
1), or combinations thereof. The protein-based and carbohydrate-based replacers
are widely regarded as fat mimetics. The fat mimetics are either proteins or carbohydrates
that have been physically or chemically processed to mimic the properties
and functions of fats in food systems; they are not fats. They tend to adsorb a large
amount of water, are not stable at frying temperature, and may produce food that is
not microbiologically shelf stable; they contribute some calories (1–4 kcal/g) to the
diet. The fat mimetics do not possess all the organoleptic, physical, chemical, and
functional properties of fats and cannot replace calories from fat on a 1:1 weight
basis. They cannot carry lipid-soluble flavor compounds because they cannot lower
the vapor pressure of lipophilic flavor molecules, and most foods prepared with fat
mimetics are often perceived by consumers as lacking in taste. Although fat mimetics
need a delivery system such as an emulsifier to carry lipid-soluble flavors, they can
carry water-soluble flavors. Some fat mimetics have mouthfeel and physical properties
approximating those of triacylglycerols but are not suitable for frying operations
because they can be denatured (protein-based substances) or caramelized (those
based on carbohydrates). They can, however, be used for baking and retort cooking
operations.
Fat substitutes are believed to be compounds that physically and chemically
resemble triacylglycerols. They are stable to high temperature cooking and frying
Table 1 Typical Examples of Fat Replacers
Compound Class
Caloric
content
(kcal/g) Absorbability Uses
Simplesse Protein-based 1–4 Absorbable FDA approved. Dairy products, dressings,
spreads. Not stable for frying and baking.
Maltodextrin Carbohydrate- 4–4.5 Absorbable Low-fat table spreads, dressings, baked
based
goods, desserts. Not stable for frying.
Olestra/ Lipid-based 0 Nonabsorbable FDA approved for savory snacks. Stable to
Olean
frying, baking, and cooking temperatures.
Supplementation with fat-soluble vitamins
required. Can be used for dairy products,
spreads, and dressing but will require separate
approval.
Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.